US pharmaceutical company Merck & Co Inc (NYSE:MRK), known as MSD outside the US and Canada, on Tuesday announced positive Phase 3 results from the HYPERION trial evaluating WINREVAIR (sotatercept-csrk) in recently diagnosed adults with pulmonary arterial hypertension (PAH) on background therapy.

WINREVAIR reduced the risk of clinical worsening events by 76% versus placebo, including all-cause death, non-planned PAH hospitalisations, atrial septostomy, lung transplantation, or disease deterioration.

HYPERION enrolled patients within the first year of diagnosis, with over 70% on double background therapy. The treatment benefit was observed within six weeks and was consistent across subgroups, including idiopathic PAH, connective tissue disease, and varying background therapies.

Adverse events occurred in 89.4% of WINREVAIR patients versus 90.0% in the placebo group, with serious events reported in 24.4% versus 28.1%, respectively. WINREVAIR also demonstrated improvements in secondary endpoints, including multicomponent improvement and maintaining or achieving a low REVEAL Lite 2 score at Week 24.

The safety profile was consistent with previous studies.

Earlier this year, the HYPERION trial was stopped early based on a review of the totality of data from the WINREVAIR clinical programme at that time, and all patients were offered the opportunity to receive WINREVAIR through the SOTERIA open-label extension study.

HYPERION followed the STELLAR and ZENITH Phase 3 studies, supporting regulatory submissions worldwide.